Realistic Uncertainties for Fundamental Properties of Asteroseismic Red Giants and the Interplay Between Mixing Length, Metallicity and $\nu_{\rm max}$
| Autor: | Li, Yaguang, Bedding, Timothy R., Huber, Daniel, Stello, Dennis, van Saders, Jennifer, Zhou, Yixiao, Crawford, Courtney L., Joyce, Meridith, Li, Tanda, Murphy, Simon J., Sreenivas, K. R. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Asteroseismic modelling is a powerful way to derive stellar properties. However, the derived quantities are limited by built-in assumptions used in stellar models. This work presents a detailed characterisation of stellar model uncertainties in asteroseismic red giants, focusing on the mixing-length parameter $\alpha_{\rm MLT}$, the initial helium fraction $Y_{\rm init}$, the solar abundance scale, and the overshoot parameters. First, we estimate error floors due to model uncertainties to be $\approx$0.4\% in mass, $\approx$0.2\% in radius, and $\approx$17\% in age, primarily due to the uncertain state of $\alpha_{\rm MLT}$ and $Y_{\rm init}$. The systematic uncertainties in age exceed typical statistical uncertainties, suggesting the importance of their evaluation in asteroseismic applications. Second, we demonstrate that the uncertainties from $\alpha_{\rm MLT}$ can be entirely mitigated by direct radius measurements or partially through $\nu_{\rm max}$. Utilizing radii from Kepler eclipsing binaries, we determined the $\alpha_{\rm MLT}$ values and calibrated the $\alpha_{\rm MLT}$--[M/H] relation. The correlation observed between the two variables is positive, consistent with previous studies using 1-D stellar models, but in contrast with outcomes from 3-D simulations. Third, we explore the implications of using asteroseismic modelling to test the $\nu_{\rm max}$ scaling relation. We found that a perceived dependency of $\nu_{\rm max}$ on [M/H] from individual frequency modelling can be largely removed by incorporating the calibrated $\alpha_{\rm MLT}$--[M/H] relation. Variations in $Y_{\rm init}$ can also affect $\nu_{\rm max}$ predictions. These findings suggest that $\nu_{\rm max}$ conveys information not fully captured by individual frequencies, and that it should be carefully considered as an important observable for asteroseismic modelling. Comment: 18 pages, 7 figures; submitted to ApJ |
| Databáze: | arXiv |
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